Real-time correction method, system, device and medium for flood simulation calculation of a river basin

Abstract

This invention discloses a real-time correction method, system, device, and medium for watershed flood simulation calculations. The method includes: determining the start time and target time period of the simulation calculation; initializing the soil moisture content at the start time of the simulation calculation and inputting it into the watershed hydrological model to obtain the simulated flow values ​​at each time point within the simulation calculation time period; calculating the simulated flood volume within the target time period; obtaining the measured flood volume within the target time period and calculating the error between the simulated and measured flood volume values ​​within the target time period; determining whether the error value is less than or equal to an error threshold; if so, outputting the optimal soil moisture content value; if not, correcting the soil moisture content and iterating; inputting the optimal soil moisture content value into the watershed hydrological model to obtain the optimal simulated flow value within the simulation calculation time period; and obtaining the optimal simulated flow value for the forecast time period after the current time. This invention can improve the accuracy of real-time flood forecast results.

Description

Technical Field

[0001] This invention relates to a real-time correction method, system, device, and medium for watershed flood simulation calculation, belonging to the field of flood forecasting technology. Background Technology

[0002] The magnitude of floods caused by rainfall is related to the amount of rainfall, the soil moisture content in the preceding period, and the characteristics of the watershed. Hydrologists use watershed hydrological models to calculate runoff generation and simulate the flow process at the predicted watershed outlet section based on actual rainfall data from rain gauges within the watershed. In southern my country, the Xin'anjiang River's full-storage runoff model is commonly used. This model only represents the runoff generated by the soil at full storage, while the soil moisture content at the forecast time is unknown. Typically, long-term calculations are performed to extrapolate the soil moisture content at the forecast time, and the uncertainty of watershed evapotranspiration can easily lead to errors in runoff calculations. Real-time forecasting systems often use real-time correction techniques to reduce errors, such as autoregressive models, Kalman filtering, and neural network algorithms. These methods use current errors to predict future errors and correct the model's forecast values. While some systems treat errors as time series and use numerical statistics and state estimation methods to predict future errors, these methods often fail to grasp the causes of errors or are too complex, resulting in poor performance. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a real-time correction method, system, device and medium for watershed flood simulation calculation, thereby solving the technical problem of inaccurate flood simulation calculation due to soil moisture content errors.

[0004] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0005] In a first aspect, the present invention provides a real-time correction method for watershed flood simulation calculations, comprising:

[0006] Obtain the current time of the simulation calculation, and determine the start time of the simulation calculation based on the current time;

[0007] Obtain the current flood peak status and combine it with the start time to determine the target time period for simulation calculation;

[0008] Initialize the soil moisture content at the start of the simulation calculation and input it into the watershed hydrological model to obtain the simulated flow values ​​at each time point during the simulation calculation period;

[0009] The simulated value of the flood volume in the target period is calculated based on the simulated values ​​of the flow rate at each moment within the simulated calculation period.

[0010] Obtain the measured value of the flood volume within the target time period, and calculate the error between the simulated value and the measured value of the flood volume within the target time period;

[0011] Determine if the error value is less than or equal to the error threshold. If yes, output the optimal soil moisture content. If no, correct the soil moisture content, replace the initial soil moisture content with the corrected soil moisture content, and return to the step: Initialize the soil moisture content at the start of the simulation calculation.

[0012] The optimal value of soil moisture content is input into the watershed hydrological model to obtain the optimal simulated flow values ​​at each time point within the simulation calculation period;

[0013] The optimal simulated flow values ​​for each time period after the current time are obtained from the optimal simulated flow values ​​for each time period within the simulation calculation period.

[0014] Preferably, the start time of the simulation calculation is the time when the minimum flow occurs within a time period T before the current time of the simulation calculation, where the time period T = watershed forecast period + 48h.

[0015] Preferably, the target time period for the simulation calculation is:

[0016] If the current flood peak status is that the flood peak has not yet occurred, then the target time period for the simulation calculation is the watershed forecast period one time prior to the current time.

[0017] If the current flood peak status is that the flood peak has occurred, but the time from the occurrence of the flood peak to the current time has not exceeded half a basin forecast period, then the target time period for simulation calculation is one basin forecast period before the current time;

[0018] If the current flood peak status is that the flood peak has occurred, but the time from the occurrence of the flood peak to the current time exceeds half of the basin forecast period, then the target time period for simulation calculation is half of the basin forecast period before and after the occurrence of the flood peak.

[0019] Preferably, the soil moisture content θ at the start time of the initialization simulation calculation is:

[0020] θ=a*Q b +c

[0021] In the formula, a, b, and c are constant parameters, with a ranging from 1 to 5, b ranging from 0.15 to 0.65, and c ranging from 30 to 60. Q is the cross-sectional flow rate at the start of the simulation calculation.

[0022] Preferably, the expression for correcting soil moisture content is:

[0023]

[0024] In the formula, θ t+1 θ t W represents the soil moisture content at the start time of the simulation calculation at iterations t+1 and t, respectively.m W s These are the simulated and measured values ​​of the flood volume within the target time period, respectively.

[0025] Secondly, the present invention provides a real-time correction system for watershed flood simulation calculations, the system comprising:

[0026] The start time determination module is used to obtain the current time of the simulation calculation and determine the start time of the simulation calculation based on the current time.

[0027] The target time period determination module is used to obtain the current flood peak status and determine the target time period for simulation calculation in combination with the start time.

[0028] The first simulation module is used to initialize the soil moisture content at the start of the simulation calculation and input the watershed hydrological model to obtain the simulated values ​​of the flow rate at each time during the simulation calculation period.

[0029] The first acquisition module is used to calculate the simulated value of the flood volume in the target period based on the simulated values ​​of the flow at each time point within the simulated calculation period.

[0030] The error calculation module is used to obtain the measured value of the flood volume within the target time period and calculate the error value between the simulated value and the measured value of the flood volume within the target time period.

[0031] The soil moisture content correction module is used to determine whether the error value is less than or equal to the error threshold. If it is, the optimal soil moisture content value is output; otherwise, the soil moisture content is corrected, and the corrected soil moisture content replaces the initial soil moisture content and returns to the first simulation calculation module for iterative looping.

[0032] The second simulation calculation module is used to input the optimal value of soil moisture content into the watershed hydrological model to obtain the optimal value of the simulated flow at each time point within the simulation calculation period;

[0033] The second acquisition module is used to obtain the optimal simulated flow rate for each time period after the current time from the optimal simulated flow rate for each time period within the simulated calculation period.

[0034] Thirdly, the present invention provides a real-time correction device for watershed flood simulation calculation, including a processor and a storage medium;

[0035] The storage medium is used to store instructions;

[0036] The processor is configured to operate according to the instructions to perform the steps according to the method described above.

[0037] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0038] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0039] This invention provides a real-time correction method, system, device, and medium for watershed flood simulation calculations. By determining a suitable start time for model calculations, it ensures that the soil moisture content at the start time affects the simulation calculations during the subsequent forecast period. It proposes a stepwise iterative process for the initial soil moisture content, selecting the target time period based on the current time and the time of the flood peak, so that the simulation results within the target time period are close to the measured results, thereby optimizing the soil moisture content. The optimized soil moisture content improves the accuracy of real-time flood forecasts. Attached Figure Description

[0040] Figure 1 This is a flowchart of a real-time correction method for watershed flood simulation calculation provided in Embodiment 1 of the present invention;

[0041] Figure 2 This is a schematic diagram of the flow rate where the flood peak did not occur, provided in Embodiment 1 of the present invention;

[0042] Figure 3 This is a schematic diagram of the flow rate provided in Embodiment 1 of the present invention, showing the occurrence of a flood peak and the fact that the time from the occurrence of the flood peak to the current time does not exceed half of the basin's forecast period.

[0043] Figure 4 This is a schematic diagram of the flow rate provided in Embodiment 1 of the present invention, showing the occurrence of a flood peak and the time elapsed from the occurrence of the flood peak to the present time exceeding half a basin forecast period. Detailed Implementation

[0044] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0045] Example 1:

[0046] like Figure 1 As shown, this invention provides a real-time correction method for watershed flood simulation calculations, comprising the following steps:

[0047] 1. Obtain the current time of the simulation calculation, and determine the start time of the simulation calculation based on the current time;

[0048] The simulation begins at the moment when the minimum flow occurs within a time period T prior to the current moment of the simulation, where time period T = watershed forecast period + 48h.

[0049] The watershed forecast period is the time from when the rainfall in the watershed center reaches the ground to when the floodwaters reach the outlet section.

[0050] 2. Obtain the current flood peak status and determine the target time period for simulation calculation based on the start time;

[0051] The target time period for the simulation calculation is:

[0052] like Figure 2 As shown, if the flood peak status at the current time Tj is that the flood peak has not yet appeared, then the target time period for the simulation calculation is the watershed forecast period one time before the current time Tj; (Ts is the start time of the simulation calculation, and Te is the end time of the simulation calculation)

[0053] like Figure 3 As shown, if the flood peak status at the current time Tj is that the flood peak has appeared, but the time from the appearance of the flood peak to the current time Tj has not exceeded half a basin forecast period, then the target time period for simulation calculation is one basin forecast period before the current time.

[0054] like Figure 4 As shown, if the flood peak status at the current time Tj is that the flood peak has occurred, but the time from the occurrence of the flood peak to the current time Tj exceeds half of the basin forecast period, then the target time period for simulation calculation is half of the basin forecast period before and after the occurrence of the flood peak.

[0055] 3. Initialize the soil moisture content at the start time of the simulation calculation and input it into the watershed hydrological model to obtain the simulation calculation period (in terms of...). Figure 2 For example, the simulated flow rate at each time point within Ts-Te is given;

[0056] The initial soil moisture content θ at the start of the simulation is:

[0057] θ=a*Q b +c

[0058] In the formula, a, b, and c are constant parameters, and their values ​​can be selected according to the characteristics of the watershed. The value of a is 1-5 (related to the characteristics of the underlying surface of the watershed), the value of b is 0.15-0.65 (related to the area of ​​the watershed), the value of c is 30-60 (related to the water storage capacity of the deep soil), and Q is the cross-sectional flow rate at the beginning of the simulation calculation.

[0059] Before inputting the watershed hydrological model, it is necessary to distribute the soil moisture content in the upper, middle and lower layers of the soil. The lower layer tension water (DW) should be satisfied first, followed by the middle layer tension water (MW), then the upper layer tension water (UW), and finally the gravity water (SW).

[0060] If θ > DM + MM + UM

[0061] Then DW=DM; MW=MM; UW=UM; SW=θ-(DW+MW+UW)

[0062] If θ > DM + MM

[0063] Then DW=DM; MW=MM; UW=θ-(DW+MW); SW=0

[0064] If θ > DM,

[0065] Then DW=DM; MW=θ-DW; UW=0; SW=0

[0066] If θ <= DM

[0067] Then DW=θ; MW=0; UW=0; SW=0

[0068] DM represents the lower layer water storage capacity, MM represents the middle layer water storage capacity, and UM represents the upper layer water storage capacity.

[0069] 4. Calculate the simulated flood volume for the target period based on the simulated flow rates at each time point within the simulated calculation period;

[0070] Flood volume is the volume of water within a time period, which can be obtained by taking the average flow rate at each moment and then multiplying it by the duration of the target time period.

[0071] 5. Obtain the measured value of the flood volume within the target time period, and calculate the error between the simulated value and the measured value of the flood volume within the target time period;

[0072] 6. Determine whether the error value is less than or equal to the error threshold. If yes, output the optimal soil moisture content. If no, correct the soil moisture content, replace the initial soil moisture content with the corrected soil moisture content, and return to step 3.

[0073] The expression for correcting soil moisture content is:

[0074]

[0075] In the formula, θ t+1 θ t W represents the soil moisture content at the start time of the simulation calculation at iterations t+1 and t, respectively. m W s These are the simulated and measured values ​​of the flood volume within the target time period, respectively.

[0076] 7. Input the optimal soil moisture content into the watershed hydrological model to obtain the optimal simulated flow values ​​at each time point within the simulation calculation period;

[0077] 8. Obtain the forecast period (in terms of time) after the current time from the optimal values ​​of the simulated flow at each time point within the simulation calculation period. Figure 2 For example, the optimal value of the flow rate at each time point within Tj-Te is calculated using simulation.

[0078] Example 2:

[0079] This invention provides a real-time correction system for watershed flood simulation calculations, the system comprising:

[0080] The start time determination module is used to obtain the current time of the simulation calculation and determine the start time of the simulation calculation based on the current time.

[0081] The target time period determination module is used to obtain the current flood peak status and determine the target time period for simulation calculation in combination with the start time.

[0082] The first simulation module is used to initialize the soil moisture content at the start of the simulation calculation and input the watershed hydrological model to obtain the simulated values ​​of the flow rate at each time during the simulation calculation period.

[0083] The first acquisition module is used to obtain the simulated value of the flood volume in the target period from the simulated values ​​of the flow at each time point within the simulated calculation period;

[0084] The error calculation module is used to obtain the measured value of the flood volume within the target time period and calculate the error value between the simulated value and the measured value of the flood volume within the target time period.

[0085] The soil moisture content correction module is used to determine whether the error value is less than or equal to the error threshold. If it is, the optimal soil moisture content value is output; otherwise, the soil moisture content is corrected, and the corrected soil moisture content replaces the initial soil moisture content and returns to the first simulation calculation module for iterative looping.

[0086] The second simulation calculation module is used to input the optimal value of soil moisture content into the watershed hydrological model to obtain the optimal value of the simulated flow at each time point within the simulation calculation period;

[0087] The second acquisition module is used to obtain the optimal simulated flow rate for each time period after the current time from the optimal simulated flow rate for each time period within the simulated calculation period.

[0088] Example 3:

[0089] Based on Embodiment 1, this embodiment of the invention provides a real-time correction device for watershed flood simulation calculation, including a processor and a storage medium;

[0090] Storage media are used to store instructions;

[0091] The processor is used to perform operations according to instructions to execute the steps according to the method described above.

[0092] Example 4:

[0093] Based on Embodiment 1, this embodiment of the invention provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the above-described method.

[0094] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0095] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0096] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0097] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0098] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A real-time correction method for watershed flood simulation calculation, characterized in that, include: Obtain the current time of the simulation calculation, and determine the start time of the simulation calculation based on the current time; the start time of the simulation calculation is: the time when the minimum flow occurs within a time period T before the current time of the simulation calculation, where the time period T = watershed forecast period + 48h; The current flood peak status is obtained, and the target time period for simulation calculation is determined in conjunction with the start time. The target time period for simulation calculation is as follows: if the current flood peak status is that the flood peak has not yet appeared, then the target time period for simulation calculation is one watershed forecast period before the current time; if the current flood peak status is that the flood peak has appeared, but the time from the time of the flood peak appearance to the current time does not exceed half a watershed forecast period, then the target time period for simulation calculation is one watershed forecast period before the current time; if the current flood peak status is that the flood peak has appeared, but the time from the time of the flood peak appearance to the current time exceeds half a watershed forecast period, then the target time period for simulation calculation is half a watershed forecast period before and after the time of the flood peak appearance. Initialize the soil moisture content at the start of the simulation calculation and input it into the watershed hydrological model to obtain the simulated flow values ​​at each time point during the simulation calculation period; The simulated value of the flood volume in the target period is calculated based on the simulated values ​​of the flow rate at each moment within the simulated calculation period. Obtain the measured value of the flood volume within the target time period, and calculate the error between the simulated value and the measured value of the flood volume within the target time period; Determine if the error value is less than or equal to the error threshold. If yes, output the optimal soil moisture content; otherwise, correct the soil moisture content, replace the initialized soil moisture content with the corrected soil moisture content, and return to step: Initialize the soil moisture content at the start of the simulation calculation. The expression for correcting the soil moisture content is: In the formula, θ t+1 θ t W represents the soil moisture content at the start time of the simulation calculation at iterations t+1 and t, respectively. m W s These are the simulated and measured values ​​of the flood volume within the target time period, respectively. The optimal value of soil moisture content is input into the watershed hydrological model to obtain the optimal simulated flow values ​​at each time point within the simulation calculation period; The optimal simulated flow values ​​for each time period after the current time are obtained from the optimal simulated flow values ​​for each time period within the simulation calculation period.

2. The real-time correction method for watershed flood simulation calculation according to claim 1, characterized in that, The soil moisture content θ at the start of the initialization simulation calculation is: θ=a*Q b +c In the formula, a, b, and c are constant parameters, with a ranging from 1 to 5, b ranging from 0.15 to 0.65, and c ranging from 30 to 60. Q is the cross-sectional flow rate at the start of the simulation calculation.

3. A real-time correction system for watershed flood simulation calculation, characterized in that, The system includes: The start time determination module is used to obtain the current time of the simulation calculation and determine the start time of the simulation calculation based on the current time; the start time of the simulation calculation is: the time when the minimum flow occurs within a time period T before the current time of the simulation calculation, where the time period T = watershed forecast period + 48h; The target time period determination module is used to obtain the flood peak status at the current moment and determine the target time period for simulation calculation in combination with the start time. The target time period for simulation calculation is as follows: if the flood peak status at the current moment is that the flood peak has not yet appeared, then the target time period for simulation calculation is one watershed forecast period before the current moment; if the flood peak status at the current moment is that the flood peak has appeared, but the time from the time of the flood peak to the current moment does not exceed half a watershed forecast period, then the target time period for simulation calculation is one watershed forecast period before the current moment; if the flood peak status at the current moment is that the flood peak has appeared, but the time from the time of the flood peak to the current moment exceeds half a watershed forecast period, then the target time period for simulation calculation is half a watershed forecast period before and after the time of the flood peak. The first simulation module is used to initialize the soil moisture content at the start of the simulation calculation and input the watershed hydrological model to obtain the simulated values ​​of the flow rate at each time during the simulation calculation period. The first acquisition module is used to calculate the simulated value of the flood volume in the target period based on the simulated values ​​of the flow at each time point within the simulated calculation period. The error calculation module is used to obtain the measured value of the flood volume within the target time period and calculate the error value between the simulated value and the measured value of the flood volume within the target time period. The soil moisture content correction module is used to determine whether the error value is less than or equal to the error threshold. If so, it outputs the optimal soil moisture content value; otherwise, it corrects the soil moisture content, replaces the initial soil moisture content with the corrected soil moisture content, and returns to the first simulation calculation module for iterative iteration. The expression for correcting the soil moisture content is as follows: In the formula, θ t+1 θ t W represents the soil moisture content at the start time of the simulation calculation at iterations t+1 and t, respectively. m W s These are the simulated and measured values ​​of the flood volume within the target time period, respectively. The second simulation calculation module is used to input the optimal value of soil moisture content into the watershed hydrological model to obtain the optimal value of the simulated flow at each time point within the simulation calculation period; The second acquisition module is used to obtain the optimal simulated flow rate for each time period after the current time from the optimal simulated flow rate for each time period within the simulated calculation period.

4. A real-time correction device for watershed flood simulation calculation, characterized in that, Including processor and storage media; The storage medium is used to store instructions; The processor is configured to operate according to the instructions to perform the steps of the method according to claim 1 or 2.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the method described in claim 1 or 2.

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